[Ovmsdev] GPS theft alert
dexter at expeedo.de
Wed Mar 10 23:09:14 HKT 2021
nice analysis & solution, merged.
Using the config macro would have been OK though, we will need to
introduce separate builds for revision 3 anyway to benefit from the
fixed SPIRAM issue.
Btw: did you find some time to do the performance tests I suggested?
Doesn't take long, just a couple of minutes.
Am 10.03.21 um 05:47 schrieb Craig Leres:
> This issue will be solved with this pull request:
> Starting with revision 2 of the ESP32, the function of the "enable
> wakeup interrupt" bit in the interrupt enable register changed to mean
> "divide BRP by 2". The OVMS SJA1000 code enables "all interrupts
> except arbitration loss" which includes the wakeup interrupt/divide
> BRP bit. This causes the can baud to be configured at half the
> requested speed; a workaround is to set the speed to 2X desired.
> The (minimal) fix is to clear this bit when revision is >= 2. Since
> we're not using sleep, we could also just always clear that bit. But
> in the long run I'm hopeful that the ability to use effectively larger
> BRP values will mean V3 hardware will be able to run can1 at lower
> speeds, e.g. 33K.
> At first I was looking at the can module in the esp-idf; even the old
> version we're running has code to do with this issue! But cleverly,
> it's a compile time #ifdef instead of run time check based on observed
> version (?!?!) I think the way it works is you define
> CONFIG_ESP32_REV_MIN to the lowest hardware version you want to
> support and it assumes you have at least that. Which seems silly to
> me. I tried converting it to a run time check and it didn't work --
> that's when I figured out OVMS uses it's own SAJ1000 driver code.
> Thanks to Thomas Heuer for reaching out to me and giving a pointer to
> this forum post:
> which was key in figuring this out.
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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